- What Panax ginseng is and potential mechanisms for how it works
- Clinical evidence to support benefit
- What L-theanine is and how it works
- Clinical evidence to support benefit
- What caffeine and citicoline are and how they work
- Clinical evidence to support benefit
Jackson, P. A., Haskell-Ramsay, C., Forster, J., Khan, J., . . . Wightman, E. L. (2021). Acute cognitive performance and mood effects of coffee berry and apple extracts: A randomised, double blind, placebo controlled crossover study in healthy humans. Nutritional Neuroscience, 1-9. doi:10.1080/1028415X.2021.1963068
Background: Polyphenols from coffee berry (chlorogenic acid) and apple (flavanol) have been shown to improve mood and increase cerebral blood flow in healthy humans. These effects may underpin the cognitive effects of polyphenols seen previously. Objective: The aim of the present paper was to extend previous research by investigating the effects of coffee berry at high and low doses when combined with apple extract on cognitive performance and mood. Design: This randomised, double-blind, placebo controlled, crossover trial included 46 healthy males and females,18–49 years of age (mean age 23 years),consuming: 1100 mg coffee berry extract, 1100 mg coffee berry extract plus 275 mg apple extract, 100 mg coffee berry extract plus 275 mg apple extract or placebo on 4 separate occasions, completing cognitive and mood assessments pre-dose and then again at 1-, 3- and 6 hrs post-dose. Results: Analysis revealed a consistent pattern of alerting effects following 1100 mg coffee berry extract. Limited effects on cognitive function were observed. Specifically, faster peg and ball performance (executive function) was observed following 1100 mg coffee berry plus apple extract and accuracy on the Rapid Visual Information Processing (RVIP) task increased on the third of four repetitions following 1100 mg coffee berry alone. Interestingly, more false alarms on RVIP were observed following the same intervention. Conclusions: In line with previous findings, 1100 mg coffee berry engendered increased arousal. The absence of effects on mood when an apple extract was added, and the potential for the low dose of caffeine within the coffee berry to act synergistically with polyphenols, raise interesting future avenues of research.
Ward-Ritacco, C. L., Wilson, A. R. & O’Connor, P. J. (2021). An apple extract beverage combined with caffeine can improve alertness, mental fatigue, and information processing speed. Journal of Cognitive Enhancement. doi:10.1007/s41465-020-00204-1
The psychological effects of low-dose caffeine combined with polyphenols from apples have rarely been explored scientifically yet synergistic effects are plausible. A randomized, double-blind, placebo-controlled cross-over experiment was used to test the psychological effects of apple extract beverages combined with 10, 20, 37.5, and 75 mg caffeine. Comparisons were made to both a placebo drink that was artificially sweetened and colored to mimic the test beverages and a positive control drink with 75 mg caffeine but without apple extract. Compared to placebo, it was hypothesized that dose-dependent improvements in cognitive performance, mood, and motivation would be realized after consuming the beverage with apple extract containing added caffeine. Outcomes were assessed before, 60 to 110, and 125 to 175 min post-beverage. The positive control beverage resulted in more serial seven subtractions, greater motivation to perform cognitive tasks, and reduced feelings of fatigue (all p < .005). The study found that psychological effects (i) were not observed for beverages containing apple extract and 10 or 20 mg caffeine, (ii) of the apple extract beverage containing 75 mg caffeine generally mimicked the effects of the positive control drink and significantly increased serial seven processing speed, and (iii) of the apple extract beverage containing 37.5 mg improved feelings of alertness and mental fatigue. In sum, effects of apple extract combined with caffeine were not dose-dependent; the apple extract beverage containing 75 mg caffeine improved information processing speed and the apple extract beverage with 37.5 mg caffeine improved feelings of alertness and mental fatigue.
Jackson, P. A., Wightman, E. L., Veasey, R., Forster, J., . . . Kennedy, D. O. (2020). A randomized, crossover study of the acute cognitive and cerebral blood flow effects of phenolic, nitrate and botanical beverages in young, healthy humans. Nutrients, 12(8), 1-16. doi:10.3390/nu12082254
Background: In whole foods, polyphenols exist alongside a wide array of other potentially bioactive phytochemicals. Yet, investigations of the effects of combinations of polyphenols with other phytochemicals are limited. Objective: The current study investigated the effects of combining extracts of beetroot, ginseng and sage with phenolic-rich apple, blueberry and coffee berry extracts. Design: This randomized, double-blind, placebo-controlled crossover design investigated three active beverages in 32 healthy adults aged 18–49 years. Each investigational beverage comprised extracts of beetroot, ginseng and sage. Each also contained a phenolic-rich extract derived from apple (containing 234 mg flavanols), blueberry (300 mg anthocyanins) or coffee berry (440 mg chlorogenic acid). Cognition, mood and CBF parameters were assessed at baseline and then again at 60, 180 and 360 min post-drink. Results: Robust effects on mood and CBF were seen for the apple and coffee berry beverages, with increased subjective energetic arousal and hemodynamic responses being observed. Fewer effects were seen with the blueberry extract beverage. Conclusions: Either the combination of beetroot, ginseng and sage was enhanced by the synergistic addition of the apple and coffee berry extract (and to a lesser extent the blueberry extract) or the former two phenolic-rich extracts were capable of evincing the robust mood and CBF effects alone.
Ding, J., Johnson, J., Chu, Y. F., & Feng, H. (2019). Enhancement of γ-aminobutyric acid, avenanthramides, and other health-promoting metabolites in germinating oats (avena sativa L.) treated with and without power ultrasound. Food Chemistry, 283, 239-247. doi:10.1016/j.foodchem.2018.12.136
Power ultrasound as an emerging processing technology has been investigated for stimulating seeds to enhance germination and accumulation of health-promoting metabolites, such as γ-aminobutyric acid (GABA) and phenolic compounds. This work was undertaken to evaluate the effects of power ultrasound (25 kHz) on the nutritional properties of germinated oats, and the microstructure of oat groats after treatment. The changes in the external and internal microstructures of the ultrasound-treated oats kernel were investigated using Environmental Scanning Electron Microscopy (ESEM) and 3D X-ray Micro Computed Tomography (Micro-CT). Physicochemical properties of oats including GABA, free sugars, avenanthramides, total phenolic content, and antioxidant capacities were enhanced after germination. Furthermore, the power ultrasound treatment for 5 min after soaking significantly enhanced the GABA (48–96 h), alanine (24–96 h), succinic acid (48–72 h), total phenolic content (24 h), and total avenanthramides (24 h) in the germinated oats.
Moser, S., Aragon, I., Furrer, A., Van Klinken, J. W., . . . Ferruzzi, M. G. (2018). Potato phenolics impact starch digestion and glucose transport in model systems but translation to phenolic rich potato chips results in only modest modification of glycemic response in humans. Nutrition Research, 52, 57-70. doi:10.1016/j.nutres.2018.02.001
Beneficial effects of some phenolic compounds in modulation of carbohydrate digestion and glycemic response have been reported, however effects of phenolics from processed potato products on these endpoints are not well known. The aims of this study were to characterize phenolic profiles of fresh potatoes (purple, red, or white fleshed; 2 varieties each) and chips, and to examine the potential for potato phenolic extracts (PPE) to modulate starch digestion and intestinal glucose transport in model systems. Following in vitro assessment, a pilot clinical study (n=11) assessed differences in glycemic response and gastric emptying between chips from pigmented and white potatoes. We hypothesized that phenolics from pigmented potato chips would be recovered through processing and result in a reduced acute glycemic response in humans relative to chips made from white potatoes. PPEs were rich in anthocyanins (~98, 11 and ND mg/100 g dw) and chlorogenic acids (~519, 425 and 157 mg/100 g dw) for purple, red and white varieties respectively. While no significant effects were observed on starch digestion by α-amylase and the α-glucosidases, PPEs significantly (p<0.05) decreased the rate of glucose transport, measured following transport of 1,2,3,4,5,6,6-d7 -glucose (d7-glu) across Caco-2 human intestinal cell monolayers, by 4.5-83.9%. Consistent with in vitro results, consumption of purple potato chips modestly but significantly (p<0.05) decreased blood glucose at 30 and 60 minutes post consumption compared to white chips without impacting gastric emptying. These results suggest that potato phenolics may play a modest role in modulation of glycemic response and these effects may result in subtle differences between consumer products.
Shi, Y., Johnson, J., O'Shea, M., & Chu, Y. F. (2014). The bioavailability and metabolism of phenolics, a class of antioxidants found in grains. Cereal Foods World, 59(2), 52-58. doi:10.1094/CFW-59-2-0052
Consumption of whole grains has been shown to reduce the risk of chronic diseases. Whole grains contain a variety of bioactive compounds with antioxidant properties that can help prevent disease by inhibiting oxidative damage. The health benefits of whole grains depend not only on the functions of the bioactive compounds they contain, but also on the quantities of those compounds consumed, their metabolism, their bioavailability in different tissues, and the functions of their metabolites in the body. This article provides an overview of grain antioxidants, including their metabolism and bioavailability, with a focus on the phenolics ferulic acid, alk(en)ylresorcinols, and avenanthramides. Ferulic acid is the most abundant form of phenolic acid found in cereal grains; alk(en)ylresorcinols are found in large quantities in rye and wheat; and avenanthramides are found only in oats. Results from in vitro, in vivo, and human studies indicate that all three phenolic compounds have potent antioxidant properties